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Looks like I got out just in time! I flew back to the UK on Thursday.
To be fair, La Palma badly needs some rain.
I am very seriously considering buying a Seestar S50.
Very impressive results have come out over the last year. Not only “pretty pictures” but also hard science. As far as I can tell, they can do precision photometry (my principal interest) down to at least 13th magnitude.
The only thing holding me back is a rumour that at 80mm version may be released Real Soon Now.
When on holiday a GP I know tells people they’re a vet.
Two things:
1) a friend of mine fell off his bicycle outside a vet’s practice. He was given excellent first aid.
2) Vets need to know at least something about almost everything medical concerning warm-blooded animals. They are generalists par excellence. To be honest, I would rather be treated for relatively minor injuries by a vet than by a brain surgeon or gynaecologist.I’m working on it, at least in part through SGL. I recently pointed out the contrast with Cambridge University, where the 160 year old Thorrowgood and 191 year old Northumberland telescopes are still in frequent use.
In the end I suspect that the Golden Rule will apply. They who have the gold make the rules. I would certainly contribute some of my (virtual) gold to a restoration effort but I doubt that I could fund it all myself. Anyone here willing to step up as treasurer of a charitable trust?
Paul
Good to see this coverage of UZ Boo and especially to see the appearance of SH’s. Hopefully these will grow.
The sky here last evening was dreadful: I could only see Vega, Altair and a very coppery Moon.Nothing from me tonight because of the strong calima. Vega and Arcturus are obvious, Deneb and Altair with some difficulty. The moon is rising. Na light pollution from El Paso / Los LLanos about 2-5km away is visible, as is that from Santa Cruz on the other side of the island with a 1500m high ridge between us. Remember that La Palma has strict regulations against emitting light upwards and they are obeyed by and large, especially municipal street lighting.
One of the worst nights I’ve seen in a long time, and I haven’t even mentioned the thin patchy cloud.
Although UZ Boo is still well placed in the sky from La Palma the sky itself has been appalling and it was not worth opening the observatory between 08-09 and 08-13 inclusive. Thick Saharan dust and high winds which create turbulence and bad seeing. Even last night A 15-pixel (8.75″) radius aperture was needed to include the bloated stars and the moonlit dust made the sky background so high that a 10 minute exposure was used to get adequate SNR. Such a time would generally let me get useful results for a target fainter than V=15.
Anyway, UZ Boo was measured at V=12.35 on 2024-08-08 and 12.75 on 2024-08-14.
Yes and no, IMO.
At the moment, and conditions may change, the “pretty picture” brigade have a readily simple mechanism to cope. They either discard subs impacted by satellites or they use (for example) sigma-rejection to discard the affected areas of their subs.
The spectroscopists and (especially) photometrists are a little more constrained. If the satellite goes over (or too close to) the target all they can do is throw away that data. For photometrists,if the satellite goes over (or too close to) a comparison it is necessary to remove that one from the ensemble for that sub. A real PITA, admittedly, but hardly crippling if there are a good number of other comparisons in the ensemble. The major problem, IMO, is teaching the pipeline to reject those occurrences without human assistance.
Gary: by “keep going” do you mean time series in a single night (like what I am currently doing for ARPS asteroidal rotational light curves) or mean making one or a few measurements per night for as long as possible?
I am hoping the latter.
Still rather easy here in the deep south.
Now taking images but it looks around V=12.3. Precise measurements will be sent to the database when the data is in.
Robin: was that with a glass prism? Glass is dense. There are much lighter transparent materials out there. Diamond may be ideal. Shame about the cost!
The printed holder may also be thinned out perhaps.
Will Tirion also drew a set of star charts specifically for the BAA, which we published in the 1980s. I covered mine in adhesive plastic and hung them up in my observatory – where they still are (well actually transferred to the warm room now, and rather yellowed). I’m thinking that due to this connection with the BAA, at least, the BAA should officially mark his passing, probably in the Journal.
David: strongly agree.
Being the owner of a Meade Schmidt-Newtonian I am almost, but not quite, concerned about its future well being. I suspect that parts and technical knowledge will still be available for the rest of my lifetime.
I strongly recommend Gravitation, aka MTW, for a comprehensive and relatively (pun intended) accessible course in classical geometrodynamics, despite it being wrotten 50 years ago.
That said, I can’t answer your question off the top of my head. Let me think about it and/or consult MTW.
Ah, I did indeed misunderstand.
Nonetheless, I was unable to edit my post after 2s and before 10h after posting. Perhaps, through UBD, I didn’t understand what the incantation should be.
Thanks.
Thanks for the explanation.
Is there a good reason why the expiry time is so ludicrously small? Other fora I frequent generally allow somewhere between five minutes and an hour. Long enough to spot speeling misteaks or to add an extra sentence of explanation, but not so long that it seriously distorts any historical perspective.
The difficulty you may find is converting the output from HOPS into one of the file formats used by the BAA. If that is difficult, then don’t bother.
Hi Andy,
Yes, quite tricky! It’s the comparison stars that are hard to deal with. As far as I can see, exploring the various output files, the pixel co-ords of the comp stars are stored in the log.yaml file, but no details about them. I could locate them on a chart and then enter that data but it will certainly be fiddly!
Cheers
Ian.How I would deal with this is to write a few scripts. It’s what I did a few years ago to upload to the BAA database.
First make sure that at least one of the images showing the target and the comparisons has an accurate WCS. If none do, astrometry.net, either on-line or self-hosted (my solution).
The coordinates of the target star are presumably well known, what are not are those for the comparisons but if you have a list of (x,y) coordinates and a WCS, the xy2sky program from the WCS tools utilities will produce a list of (RA,Dec) coordinates. Easily scriptable.
Given those, from I download a subset of the GAIA catalogue centred on the target and wide enough to include all the comparisons. Quarter to half the FOV is a reasonable estimate. https://vizier.cds.unistra.fr/viz-bin/VizieR-3?-source=I/350&-out.max=50&-out.form=HTML%20Table&-out.add=_r&-out.add=_RAJ,_DEJ&-sort=_r&-oc.form=sexa is a starting point. Customize the search fields until you have nailed down the query you want, then copy the URL for use as a prototype in subsequent searches. I tend to ask for the J2000 coordinates, either G magnitude or RP magnitude (depending on whether the images were unfiltered or V for the former, R or SR for the latter) and its error, and the G-RP value. Ask for lots of lines in tsv format.
Given that data, filter out all stars which are more than a few magnitudes brighter or fainter than the target. Reject all stars which are markedly different colour from your target. Finally, search in the remainder for stars which lie within a few arcsec of the list of coordinates you produced earlier. Remember that stars have proper motions; I have been bitten by this one before!
After all that, you have a sequence of comparison stars ready to be fed into your regular photometry program.
This is my procedure for exoplanets where good sequences do not exist at, say, AAVSO, and for asteroids where they rarely do so.
If you speak Perl, there’s a good chance that much of the scripting required can be provided. Contact me off-list if you wish to give it a try.
Good luck!
